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4.9 liter engine coolant change method? 'recap'


the gold2

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Hello , I don't mean to nauseate the edified group on this forum, but I have read many archived threads on changing the coolant in CaddyInfo.

Most threads refer to the Northstar engine and the majority of knowledgeable folks seem to state that they literally just undo the lower radiator hose and drain out whatever drains, then measure that volume of removed coolant/water mix, and lastly replace that same volume with a new 50-50 mix of coolant and water. Nothing more than that.

So, say you drain 4 quarts of old coolant mix, you then replace with 4 qts of new coolant /water mix. Nothing more until 2 years later.

That seems to be the consensus for Northstar engines assuming the coolant is replaced every 2 years.

My question is whether the 4.9 engine (1992 Eldo Touring Coupe) can be treated the same way without any problems or engine parts deterioration later.

The Eldo FSM directs one to drain the radiator, fill with water only, operate engine enough to open thermostat, drain again and repeat the sequence until drained radiator fluid is clear.

THEN replace with new coolant in such volume to obtain a 50-50 mix inside the entire syatem.

Again, what I am not clear on is whether I can employ the quicker and cleaner 'consensus' method or should I just do the FSM method (more time, more mess) ?

P.S. the 4.9 Lt. engine is spec'd for basic green, ehtylene glycol-GM 1825_m, antifreeze. I like to replace/renew every 2 years and add Bars Leak tablets. (mechanic did it last time- had the car 2 years now)

The engine holds 12.1 qts of coolant.

So I figure I need to add 1.5 gallons of straight coolant into the ' last sequence- emptied radiator ' to get a 50-50 mix assuming I do the FSM method.

Right?

Please help me get clear on this.

Much thanks to this great forum.

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Ill let others comment but make sure you use the cooling supplement tablets in the 4.9. I was in an AC DELCO distributor the other day and they had a large supply But other members here have used Bars Leak tablets.

The only problem I have with putting water in is 1) inducing minerals into the system from the water and 2) this creates a problem balancing the system to 50/50 with the straight water in the system

Green coolant is fine every 2 years.

If I recall, the guru used to say, just drain and refill

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The only time I fould flush the system is if is had a lot of crud in it visible in the radiator. I don't remember if the 4.9 engine has block drains. If there are block drains, you can get almost all the coolant out of the block.

The cooling system sealant pellets/Bars Leaks is mandatory in the 4.9 engine (as well as the 4.5 and 4.1) due to the wet sleeve cylinder design.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I would go with the owner's manual myself. But the guru knows his stuff; if the coolant is clear, the color is good, and you are absolutely sure that you won't go over two years, then, sure, drain and refill.

You can get distilled water for $1/gal at Wegman's or about half that at WalMart. Caveat emptor; I saw it for $20/gal on Amazon.

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Hey all, thank you very much for your comments. Any others' experiences and knowledge ? Especially 4.9 liter engine owners?

Yes I do plan on replacing coolant every two years and do insist on the manufacturer recommended green coolant.

This is my weekend fair weather car, so I don't put many miles on it (under 2K per year) nonetheless I do keep maintenance schedules on my cars.

I now feel better about possibly doing a simple drain and refill (and will use distilled water and coolant supplement) but want to make sure since most folks' experience is with a Northstar engine whose dexcool antifreeze may have other properties than the simple green ethylene glycol.

Any 4.9 liter owners out there?

Thanks again.

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Let a 4.9 owner who kept it in good shape for 9 years and 100,000 miles chime in. :)

Firstly, unlike Northstar, 4.9 lets you SIPHON old coolant out of radiator neck. Just get some 4 feet of 1/4" diameter PVC tube, fill it with water, plug one and and push the other end to the bottom of the radiator through the filler neck. It is tight fit, but you can do that.

Let as much old coolant to be siphoned as possible. About a gallon is normal. Replenish with fresh coolant, add a tube of Bars Leaks Golden Seal powder from Wal-Mart or tablets from dealer into the radiator neck (not the reservoir) . They both are made by the same company.

Repeat this procedure every other year. Probably skip that Bars leaks stuff once in a while. Do not worry about old coolant left in engine.

After a couple of heating/cooling cycles, add some coolant into the reservoir.

The engine will get rid of any air pockets independently, no bleeding is required. I loved 4.9 engine cooling system and absolutely hate one of my 5.7 Chevy engine. :(

The saddest thing in life is wasted talent

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I loved 4.9 engine cooling system and absolutely hate one of my 5.7 Chevy engine. :(

What's the issue with the cooling system on the LT-1?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Here's my take on this whole issue. You can go ahead and flush to your heart's content, FSM and all! All you need to do is ensure that after you have done everything that you want to do, is that you can somehow satisfy yourself that the final mixture of green ethylene-glycol / pure, uncontaminated (distilled), water, is at the recommended concentration. This can easily be achieved by ensuring that you've completely drained every place in the engine block and that it doesn't hold any pockets of undrained residue from anything you've added prior to refilling, which includes any acid meant for "cleaning" the system, or just plain water. This includes opening any block drains, which the 4.9 does NOT have. Then refilling the engine with a 50/50 mixture that you made in a 5 gallon bucket, of pure antifreeze and distilled water.

OR

You can open the lower radiator drain, if you have one, flush the rad (only) with a hose, since you know it will empty completely, close everything up and refill it with 50/50 mix.

Which method sounds easier to you? Doing this every two years I'd pick method #2.

I know I'm being abrasive and abrupt, and I'm sorry for that, but I've had problems with cars in the past that have developed leaks in the transmission cooler (in the radiator side tank) due to flushing chemicals left in the radiator after a thorough cleaning and rinsing. I also own a refractometer to determine that my engine is indeed at a 50/50 mix of coolant. You can get one of these for about $45.00 if you want to check your concentration of ethelye-glycol solution.

adallak has good advice using the siphon method if you do not have a radiator drain, but that kind of prevents any kind of flushing.

Never underestimate the amount of a persons greed.

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I loved 4.9 engine cooling system and absolutely hate one of my 5.7 Chevy engine. :(

What's the issue with the cooling system on the LT-1?

IMHO, it is overengineered. A lot of people on implalass forum bypassed the throttle body. Even GM recommended some modifications so the heater would work more efficiently. Bleeding is another story. Unlke 4.9 engine, LT1 may never get rid of air pockets. You have to bleed it with the front of the car up and take special measures so that coolant would not wet the optispak (distributor). Here is my post about coolant loss on the other forum, if you are interested to have a look.

http://www.impalassf...ad.php?t=277064

The saddest thing in life is wasted talent

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I loved 4.9 engine cooling system and absolutely hate one of my 5.7 Chevy engine. :(

What's the issue with the cooling system on the LT-1?

IMHO, it is overengineered. A lot of people on implalass forum bypassed the throttle body. Even GM recommended some modifications so the heater would work more efficiently. Bleeding is another story. Unlke 4.9 engine, LT1 may never get rid of air pockets. You have to bleed it with the front of the car up and take special measures so that coolant would not wet the optispak (distributor). Here is my post about coolant loss on the other forum, if you are interested to have a look.

http://www.impalassf...ad.php?t=277064

I've worked on cooling systems on a 1994 Fleetwood and didn't have the issues you were describing. I only got a gallon of coolant out of the radiator. Once I pulled the knock sensors on the block, the rest came out. The air bleed wasn't much of an issue since I had the car up on ramps anyway.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Many of us like myself owned 4.9's, I had a 91 Seville before my 96 Deville.

Keep in mind that the 4.9 is an aging platform and the last time it was used was in the 95 Deville, the 95 Deville Concours had a Northstar, so it is at least 18 model years old

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Let a 4.9 owner who kept it in good shape for 9 years and 100,000 miles chime in. :)

Firstly, unlike Northstar, 4.9 lets you SIPHON old coolant out of radiator neck. Just get some 4 feet of 1/4" diameter PVC tube, fill it with water, plug one and and push the other end to the bottom of the radiator through the filler neck. It is tight fit, but you can do that.

Let as much old coolant to be siphoned as possible. About a gallon is normal. Replenish with fresh coolant, add a tube of Bars Leaks Golden Seal powder from Wal-Mart or tablets from dealer into the radiator neck (not the reservoir) . They both are made by the same company.

Repeat this procedure every other year. Probably skip that Bars leaks stuff once in a while. Do not worry about old coolant left in engine.

After a couple of heating/cooling cycles, add some coolant into the reservoir.

The engine will get rid of any air pockets independently, no bleeding is required. I loved 4.9 engine cooling system and absolutely hate one of my 5.7 Chevy engine. :(

The northstar radiator and engine can be emptied in 5 seconds by taking the lower radiator hose off and directing it into a cement mixing tub..., no brainer, very easy. The Northstar's air purge line works perfectly and its ingenious. My 3.4 Monte Carlo has a manual air purge that must be opened by hand, not a biggie, but it surely ain't a Northstar

I think the water pump on the 4.9 sucked, it gave you about 5 minutes worth of a warning before it put you on the side of the road with the serp belt wrapped around the accessory wheels. I had about 135,000 miles on that car, loved it.

That said, I loved the 4.9, I really did, but the water pump sucked, it left me on the side of the road twice, it would not last long enough even to get me to an exit, 5, 4, 3, 2, 1 bam 260 degrees, no steering, no charging, lights all over the dash.... Plus, I didnt buy used pumps, I bought new pumps, PLUS, I replaced my idler wheels, tensioners, etc and the serp belt was perfectly in line with no wobble in the belt accessories, it just went out

My daughter is 15 and at the time was about 3, and STILL remembers standing behind the guard rail because 18 wheelers and cars were going by at 75, while we were on the shoulder with steam comming out from under the hood and the serp belt wrapped around everything, in the dark at 9 PM, I was afraid to stay in the car for fear someone would hit us in the light rain, that was a 22 mile flat bed trip to a Marriott Hotel. I put a new pump in behind the Marriott with borrowed tools from the super, my wife took photos of me under the hood behind the marriott. That job which took probably 3 hours in the cold, having to take a taxi to an Autozone to get parts twice once for tools.... was a bear

It is important to note that most of my driving is high speed highway driving at the time and I tended to wind that engine out a lot, so it could have been the type of driving I did. One other thing, I did have the #1 main bearing knock pretty badly at times, so maybe the knock set up some sort of vibration or harmonic that caused damage to or overheated the bearing... but that is just a thought, who knows because, I dont know many others that have complained here about the pump's durability over the last 15 years besides me. But at about 40,000 miles, it just self destructed at about 75 mph in the worst possible location for me twice, with no prior warning like in the old days, I am under the hood and listen to the engine very carefully and there was never a warning! :lol:

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Hey Folks, lots of interesting information imparted here.

And all well taken.

So the 4.9 liter has no block drains and for the sake of the consistent 2 year coolant maintenance service, doing a simple drain and replenish is a sound practice.

So that is what I will be doing.

BodybyFisher, I now recall your water pump anecdote from another thread. Man what an ordeal !

My '92 Eldo's service records from the original owner show that at least he was able to note fluid drips on his garage floor which lead him to have it serviced at the dealer. Yup, the water pump had to be replaced at about 38,279 miles in 2003 (so original one lasted 11 yrs of moderate driving behavior).

Thanks all for the great info and supportive knowledge.

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By the way, if you did not replace the radiator, your inlet side tank (driver side) is probably about to develop a vertical crack in the upper part facing the fans.

The saddest thing in life is wasted talent

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I drove that car like a madman, and it took a beating. Amazing car

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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